This is a non-controlled, observational study. Physiological endpoints: MAP (mean arterial pressure); etCO2 (end-tidal expiratory pCO2); ROSC (return of spontaneous circulation); PaO2 (arterial pO2); PaCO2 (arterial pCO2); endpoints to assess feasibility: time from arrival to start of mechanical compressions, problems during transfer into the helicopter and in-field manoeuvers, problems with application of device, problems with patient transfer to hospital premises, hands-off time, personnel requirements.